Add support for tracking credential usage

[tsalzinger]

What feature do you want to see added?

The plugin should call the approproate variants of CredentialsProvider.track for:

• Repo scanning
• Branch scanning
• Pipeline executions (in case the configured credentials are also used for the actual checkout)

This will help with keeping track of which credentials are used where.

Upstream changes

No response

Are you interested in contributing this feature?

yes, I have a working draft already and I'll open a PR for further discussion / gathering feedback on the specific impelmentation soon